mark kibort

Ok folks, I got the alignement adjusted back after my little hit at the track.
.5" of toe was only 2.5 turns of the tie rod to get it right again. BUT, i noticed the caster, or more accurately, the distance between the front and rear wheels.
Has anyone ever measured the distance between front and rear hubs? I got 98 and 98.5" . a little shorter on the hit side and that front wheel is visually closer to the rear of the front fender. I should just put it on a rack , but it drives well and the steering is straight again.
what is the effect of one wheel with less caster than the other as far as handling if toe and camber is good?

Bill Ball

Car would pull to the side with less positive caster. The adjuster moves the wheel forward to reduce caster.

What do you mean by 0.5" toe (measured how?). 2.5 turns of the tie rod is a lot. Did the tie rod get bent? Maybe the lower balljoint got mooched too.

mark kibort

the front of the front wheels compared to the rear of the front wheels. (a trapazoid) normally, I run 1/8th toe in. I was .5" toed in after the impact. tie rod was not bent, and .5" is not very much distance on the tie rod adjuster, as the pitch is pretty fine for the 2.5 turns. IF you look at the system, you can see a lot of the struture could have bent ever so slightly. ball joint at the tie rod ends look fine, and have no binding or visual damage. I bet that long spindle arm bent a little.

the car runs true as it did before. no pulling and the wheel is centered again.
I had a crude measurement of the the distance of the front and rear wheels to each other. .5" seems like a lot too on that dimension.

mk

tlsmith1999

Mark,
When I had the alignment done on my '89, the passenger side caster would not adjust positive enough. Ended up replacing the lower ball joint. The holes that the eccentrics sit in were stretched, not allowing a correct adjustment. I could see nothing wrong with it until I remove the eccentrics completely. Not sure if this helps any.

dr bob

Mark, the 0.5" toe you state means nothing without some dimensions on the trapezoid. Use a standard measurement unit like degrees/minutes/seconds. Or is your 0.50" really half a minute?

If the tire is now closer to the rear of the fenderwell, it's very likely that the frame rail is tweaked where the lower arm attaches. The WSM gives some of the dimensions you can measure to see how much twist you've added. Half an inch is way out of the normal adjustability range on the lower ball joint, so you'll probably need to get that all straightened up before you can get a valid alignment. If it's just the lower arm pulled back by the bent frame, you wonn't be able to get the caster set corectly. If there really is 1/2" at the middle, that means the lower arm is about 1" to the rear, and your caster is negative. Probably don't want to drive it that way at all, since the steering on that wheel will try to go away from center. Very Dangerous!!

A good frame shop should be able to tell you how much it was tweaked and whether they can safely restore it for you. Or maybe you got real lucky and just bent the control arms. Those you can just buy and bolt in. Your tape measure will tell you a lot, with the WSM dimensions. Start off with simple diagonal measurements from the rear suspension bolts and you'll know instantly where things have moved.

mark kibort

thanks!

The toe in is the width of the tire (about 24") when looking at the trapazoid.
The top of the trapazoid is 1/8" closer than the bottom (rear of the tires)
71.5 vs 71 5/8" for the rera of the tire. 1/8" toe in. was .5" However, the impact was just a nick in the rim at the front i suspect as it increased the toe. but you never know, it was a good little smack. the caster is just a rough guess as I put a mark wheel center to wheel center front to rear. Looks like one side is 5" shorter than the other, but that could be off due to measuring technique. the toe i do is very accurate and used to confirm it on the hunter machine within a few %. (both camber and toe)

the ony think I cant check is caster and the relationship of the rear tires to the front.

as far as the f/r wheel spacing. it was a total number i was measuring. I dont understand what you mean by a half way point and I could acutally be 1" off. I guess the diagnals is what i need to measure. where do I take these measurements? ride hight measuring pads ???

mk

mark kibort

1.5 degrees toe in (was) now 20min(.35 degrees) toe-in after 2.5 turns of the tie rod .

.5"/20" diameter of the tire where measured, INV TAN = 1.5 degrees toe.

Bill Ball

Did I get the caster setting backwards again?

Bill Ball

Mark: If the tie rod was not bent but toe moved that much, something else is very bent.

GlenL

Check the ball-joint studs

mark kibort

how? it all looks pretty solid. no visual bending of any thing.
the tie rods couldnt bend, as they were getting stretched. more toe means more extenstion . it means that spindle arm that attaches to the tie rod had to bend slightly. (fractions of an inch to create a .5" movement at the wheel front)

is the ball joint you are talking about at the bottom of the spindle arm? or the ball joint where the essentrics are I dont think that would be the bending area, as they would have to be pushed in or forward substantially, and that would change the camber and the camber is unchanged

mk
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dprantl

I just recently adjusted my toe, and on my car one full turn of the tie rod (360 degrees) turned out to be approximately 2.1 degrees of toe. So it is a LOT. I used a method similar to yours, Mark, except I used a long straight piece of wood to extend out the measurement to make it more accurate than just measuring using the 18" of the wheel.

Dan
'91 928GT S/C 475hp/460lb.ft

GlenL

The stud on the lower ball-joint (at the end of the lower control arm) could be bent. That'd produce some odd effects.

svp928

MArk you may have to run string around the car to get real idea of what happened- but if the wheelbase is off .5" from one side to the other, something is very wrong. They should be as close to the same as possible...You will have to find out what moved before you can go on...

Bill Ball

Exactly my point.